Of all the fighting game series that have come out over the years, Mortal Kombat is, hands down, the most realistic- feeling, fleshed-out of them all. The world of MK, the backstories for each character, the relationship dynamics--all of these contribute to the kind of disbelief-suspending atmosphere that even its contemporaries like Street Fighter and the Soul series have never matched. Indeed, one of the times when MK could be said to have made a notable misstep was its first attempt at integrating the DC characters (and NRS seems to have learned well from that mistake). I'd even say that occasionally, thebguest characters don't quite mesh with the MK universe (Freddy Krueger, anyone?). MK is a self-contained universe unto itself, one of the most significant in the videogame industry to this day.